Fluid pressure brake



Nov. 19, 1935 J c, McCUNE 2,021,798

FLUID PRESSURE BRAKE Filed Dec. 3, 1930 I N VEN TOR.

JOSEPH C. MCCUNE ATTORNEY. -89

Patented Nov. 19, 1935 UNITED STATES PATENT OFFICE The Westinghouse AirBrake Company, Wilmcrding, Pa., a corporation of PennsylvaniaApplication December 3, 1930, Serial No. 499,741

13 Claims.

This invention relates to fluid pressure brakes, and more particularlyto a brake equipment in which the brakes are applied by effecting areduction in brake pipe pressure and are released by increasing. thebrake pipe pressure.

An object of the invention is to provide an improved fiuid pressurebrake equipment in which means are provided for producing a highemergency brake cylinder pressure when an emergency application of thebrakes is made.

Another object of the invention is to provide an improved fluid pressurebrake equipment in which means are provided by which the brake pipe isquickly recharged after an emergency application of the brakes.

Another object of the invention is to provide an improved fluid pressurebrake equipment of the character mentioned which is relatively simple inconstruction, and reliable and exact in function under all conditions ofservice.

The invention also comprises certain new and useful improvements in theconstruction, arrangement and combination of the several parts of whichit is composed, as will be hereinafter more fully described and claimed.

In the accompanying drawing, the single figure is a diagrammatic view ofa fluid pressure brake equipment embodying the invention.

Referring to the drawing, the equipment may comprise a brake pipe 6.auxiliary reservoir 1, triple valve device 8, brake cylinder 9, quickservice valve device IO, serial release reservoir II,-

and a high pressure valve device I5.

The triple valve device 8 may be of well known construction andcomprises a casing having a chamber l2 connected to the brake pipe 6,through a passage i3 and containing a piston it having a stem l5 adaptedto operatively engage a main slide valve l6 and an auxiliary slide valvei1 contained in a chamber i8 connected to the piston chamber l2 throughthe usual feed groove l9 around the piston i4 and also connected to theauxiliary reservoir 1 through a pipe 20. Also contained in the valvechamber i8 is a retarded release stop 2i which is subject to thepressure of a spring 22 and which is adapted to be engaged by the end ofthe piston stem i5. Contained in the piston chamber i2 is the usual sprng-pressed graduation stem 23 with which the piston i4 is adapted toengage.

The triple valve device 8 also comprises a quick action piston 24contained in a chamber 25 and adapted to operate a quick action valve 26contained in a chamber 21. Also contained in the chamber 21, is a checkvalve 28 having a central bore containing a spring 29 with which aprojection 30 on the valve 26 cooperates. The cham-' her 3! at one sideof the quick action piston 24 is connected to the brake cylinder 9,through a passage and pipe 32. Passage 32 also leads to 5 the seat ofthe main slide valve i6.

The quick service valve device in may comprise a casing having a pistonchamber 33; connected through a passage 34' with the auxiliary reservoirpipe 20 and containing a piston 35 and having a valve chamber 36,connected through a passage 31 with the brake pipe 6 and containingaslide valve 38, adapted to be operated by piston 35.

On one side of the piston 35 there is a spring step 39, while on theopposite side of said piston I there is a spring stop 40, which ismounted in the valve chamber 35 and. engages the end of the piston stem.The construction is such that when the device is in release position, asshown in the drawing, the piston 35 is held between the spring stops 39and 50, and movement of the piston in either direction is opposed bysaid spring stops.

.Also mounted in the casing of the quick serv: ice valve device iil, isa flexible diaphragm ll, having at one side a chamber 42 containing aspring 43 which urges said diaphragm. into engagement with a seat rib 44at the opposite side of the diaphragm, said seat rib separating anannular chamber 45 from a chamber 56 when the diaphragm is seated.

The high pressure valve device i5 may comprise a casing having a pistonchamber it, connected to the brake pipe passage 31 heretofore referredto and containing a piston i1 and having a valve chamber '18 connectedthrough passages 50 and iii with the serial release reservoir ii andcontaining a slide valve 19 adapted to be operated by piston 11.

On one side of the piston 11 there is a spring 80, while on the oppositeside of said piston there is a spring stop 8 i, which is mounted in thevalve chamber 18 and engages the end of the piston stem. Since thepiston TI is held between the spring 80 and the spring stop 8i, movementof the piston in either direction is opposed thereby.

In operation, when the brake pipe 6 is charged with fluid under pressurein the usual manner, fluid flows from the brake pipe through passage i3to piston chamber i2 of the triple valve device 8 and shifts the pistonM to release position, as shown in the drawing.

Fluid then flows from the piston chamber I2, through the feed groove B9to valve chamber l8, and from valve chamber I8 through pipe 20 to I theauxiliary reservoir 1, thus charging the auxiliary reservoir 1, and thevalve chamber l3.

Fluid also flows from the pipe 20, through passage 34 to the pistonchamber 33 01' the quick service valve device l8, and from passage 34through passage 82 to the seat of the slide valve 19 of the highpressure valve device 15. Since the diaphragm chamber 42 is connected tothe passage 34 by passage 41, fluid also flows to the chamber 42. Fluidalso flows to the serial release reservoir II from passage 34, throughpassage 48, past ball check valve 49, and passage 59. From passage 50,fluid flows past ball check valve 52 and through passage 53, to theannular chamber 45. From passage 50, fluid also flows through passage 5|to the valve chamber 18 of the high pressure valve device 15.

It will thus be noted that when the piston l4 of the triple valve device8 is in release position, as shown in the drawing, and the auxiliaryreservoir 1 is charged with fluid under pressure, piston chamber 33 anddiaphragm chambers 42 and 45 of the quick service valve ID, the serialrelease reservoir II, and valve chamber 18 of the high pressure valvedevice 15, are also charged with fluid under pressure, as suppliedthrough the auxiliary reservoir pipe 20.

The valve chamber 33 of the quick service valve device In is chargedwith fluid under pressure from the brake pipe 8, through passage 31.Therefore, with the chambers 33 and 36 both charged with fluid underpressure in the manner described above, the piston 35 is held in releaseposition, as shown in the drawing, by the spring stops 39 and 40.

The piston chamber 16 of the high pressure valve device is charged withfluid under pressure from the brake pipe 6, through passage 31 and withthe valve chamber 18 on the opposite side of the piston 11 charged withfluid under pressure as supplied through the auxiliary reservoir pipe20, in the manner described above, the piston 11 is held seated againstthe seat rib 83, by heavy spring 80.

With the triple valve device 3 in release position, the brake cylinder 9is connected to atmosphere, through pipe and passage 32, cavity 54 inthe slide valve l6, and passage 55.

With the quick service valve device I!) in release position, chamber 45above the diaphragm 4| is connected to atmosphere, through passage 56,cavity 51 in the slide valve 38, and passage 58 Associated with thequick service valve device 10, is a reduction limiting reservoir 59which is connected to atmosphere, when the equipment is in releaseposition, through passage 60, valve cavity 51 and passage 58, passage 60being provided with a restriction or choke 14.

When it is desired to effect a service application of the brakes, thebrake pipe pressure is gradually reduced in the usual manner. When thebrake pipe pressure has been sufllciently reduced in piston chamber I 2of the triple valve device 8 below that in-valve chamber l8 on the,other side of piston l4, the higher pressure on closed, so that backflow from the auxiliary reservoir to the brake pipe is prevented.

Further movement 01' the piston l4 causes the movement 01 the main slidevalve l6, but this movement requires a suflicient differential of 5pressures between the auxiliary reservoir and the brake pipe to overcomethe frictional resistance of the main slide valve to movement.

The reduction in brake pipe pressure is also efiective on the quickservice valve device I3, 10 and as soon as the pressure in valve chamber33 has been sufliciently reduced below that in pison chamber 33 on theother side of the piston 35, the higher pressure on the auxiliaryreservoir side of said piston is able to overcome the 5 resistance ofthe spring stop 40 and move the piston 35 and slide valve 38 to theright.- The movement of the slide valve- 38 first closes the connectionbetween the reduction reservoir 53 and the atmosphere, through passage30 and the valve cavity 51, and then uncovers the, passage 60, so thatthe valve chamber 36 is connected with the reduction reservoir59.Fluid,under pressure then flows from the brake pipe 3, through valvechamber 35, to the reduction reservoir 59, causing a quick localreduction in the brake pipe 8 and in the piston chamber l2.

Due to the action of the quick service valve device ID, the brake pipepressure in piston chamber l 2 is quickly reduced, so that the higher 39pressure on the auxiliary reservoir side of piston I4 is able toovercome the resistance of the main slide valve l6, and the movement ofthe piston l4 and slide valve I6 to the left is assured.

The movement of the main slide valve I6 closes the connection betweenthe passage 32 and the cavity 54 which is connected with the exhaustport through passage 55, and brings uncovered port 62 into partialregistration with passage 32. Fluid under pressure then flows from theaux iliary reservoir 1 to the brake cylinder 9, through port 62 andpassage and pipe 32.

At the same time, the first movement of the auxiliary slide valve l1,connects two ports 63 and 64 in the main slide valve l6, through cavity65 in the auxiliary slide valve l1, and the movement of the main slidevalve l6 brings port 83 i to register with port 68 in the slide valveseat,

and port 64 with port 81. Consequently, fluid in chamber 21 flowsthrough ports 66, 63, 65, 64 and 51, thence around the quick actionpiston 24, which fits loosely in its cylinder, to chamber 3| and to thebrake cylinder. v i

When the pressure in chamber 21 has reduced below the brake pipepressure. remaining in chamber 68, the check valve 28 is raised andallows brake pipe fluid to flow past the check valve and through theports 68, 63, 65, 84 and 6-1 to the brake cylinder. The size 01' theseports is so proportioned that the flow of fluid from the Q0 brake pipeto the top of the quick actionpisto'n 24, is not sufficient to force thepiston 24 downvalve device I0 is connected to the auxilia y 1188- 55ervoir 1, the pressure 0! fluid in said chamber reduces as fluid flowsfrom the auxiliary reservoir to the brake cylinder in applying thebrakes.

r When the reduction of the pressure of fluid in piston chamber 33approaches equalization with 7 the reduced brake pipe pressure in valvechamber 36, on the opposite side of the piston 35, the spring stop 40moves piston 35 and the .slide valve 38 to the left toward releaseposition.

The movement of the slide valve 38 first laps 15 1 nipulationthe-passage 90, thereby closing the connection between the reductionlimiting reservoir 59 and the brake pipe and then connects passage 69.through valve cavity 51, with the atmospheric passage 58, so that fluidin the reduction limiting reservoir 59 is vented to the atmosphere.

When the triple valve device moves to service position, fluid is ventedfrom the auxiliary res ervoir to the brake cylinder at a rate fasterthan the brake pipe pressure is reducing, so that the triple piston issoon moved by a preponderance of brake pipe pressure to lap position. Asthe reduction in brake pipe pressure continues however, the triplepiston will again move to service application position and then back tolap and this movement between service and service lap positionscontinues so long as the reduction in .brake pipe pressure continues.

It should be noted that the quick service valve device Ill returns torelease position just prior to the triple valve assuming service lapposition. As the reduction in brake pipe pressure proceeds, the

'quick service valve device l0 again takes up its quick service ventingposition and remains in this position approximately until the triplevalve device, after having moved to service position, returns again toservice lap position. It will be noted, therefore, that the quickservice valve device lll functions not only to propagate a brakeapplication throughout the train with great rapidity but also to ventthe brake pipe locally throughout the train, thus reducing the quantityof fluid to be discharged at the engineer's brake valve, and insuringthat effective braking action will be obtained quickly and uniformlythroughout the train.

' Fluid continues to flow from the auxiliary reservoir 1 through port 62and passage 32 to the brake cylinder 9, until the pressure in the valvechamber I8 becomes enough less than that of the brake pipe to causepiston I4 and auxiliary slide valve H to move to the right until the'shoulder I2 on the piston stem strikes the left hand end of the mainslide valve l6.

As the friction of the piston l4 and auxiliary slide valve I! is muchless than that of the main slide valve it, the diiierence in pressurewhich -will move the piston and auxiliary slide valve, will not besufficient to also move the main slide valve, consequently, the pistonstops in the position in which the auxiliary slide valve l1 blanks port62, thus cutting off any further flow of fluid from the auxiliaryreservoir to the brake cylinder. In this position, the auxiliary slidevalve I! also blanks the port 63, thus preventing further flow throughthe quick service ports. Consequently, no further change in fluidpressure can occur, since all ports are lapped.

If it is desired to make a heavier application, a further reduction inbrake pipe pressure by maof the engineers brake valve (not shown) ismade, and then the operation of the valve devices described aboverepeated, until the auxiliary reservoir and brake cylinder pressuresbecome equalized.

It should be noted that the high pressure valve device remains inactivewhen a service application of the brakes is initiated, since the springBil-is of such value that a greater differential on piston 11 isrequired to compress spring 80 than is needed to move the pistons l4 and35 of the triple valve device and quick service valve device,respectively.

When it is desired to release the brakes, the

brake pipe pressure is increased in the usual way by moving theengineer's brake valve to full release position, which consequentlyincreases the pressure of fluid in piston chamber l2 0! the triple valvedevice 3 and in valve chamber 35 of 5 the quick service valve device It,so that the piston i4 is moved to the right toward its release position,while the piston 35 is moved toward the left. 2

The spring 39 is of such value that, normally, a 10 greater diflerentialon piston 35 is required to. compress spring 39 than is needed to move'pisto'n l4 in the triple valve device to release position. In theordinary case, therefore, piston l4 moves to release while piston 35remains in its normal 13 or running position. If, however, the increasein brake pipe pressure is suiiiciently rapid, as is the case at the headend of the train, the differential on piston 35 is further increasedbecause the feed groove l9 does not permit a sufficient flow oi fluid toallow the pressure in the auxiliary reservoir I to increase at the samerate as brake pipe pressure increases in piston chamber 12.Consequently, piston I4 is forced further to the right compressingspring 22 and causing the triple 25 valve device to take up the wellknown retarded release position.

When the increase in brake pipe pressure is sutficiently rapid to buildup a difierential on piston l4 causing it to move to retarded releaseposition, it is obvious that spring 39 in the quick service valve deviceIn can be given such a value that,

'through passage 56 to chamber which is opeiito the inner seated areaformed by the seat rib With release reservoir pressure in chamber 45,brake pipe pressure in chamber 43, and auxiliary reservoir pressure inchamber 42, the diaphragm 4| will be moved away from its engagement withseat rib 44, compressing the spring 43, since auxiliary reservoirpressure in chamber 42 will be lower than the brake pipe pressure, whenthe brakes are being released, i

The movement of the diaphragm 4| away from the seat rib 44 connectschambers 45 and 46, and the serial release reservoir II is connected tothe brake pipe 6 by way of passage 53, past check valve 52, passage 53,chamber 45, chamber 46, passage 69, past ball check valve 10, andpassages H and 31, so that a sudden increase in brake pipe pressure isproduced.

When the auxiliary reservoir pressure is built up to a suflicientdegree, the spring stop 39 returns piston 35 and slide valve 38 of thequick service valve device ID to release position.

In the retarded release position, cavity 54 in the main slide valve l6registers with brake cylinder passage 32, while a. passage 13 having arepressure which is transmitted to cars at the rear of the cars adjacentto the engine, so that the rate of increase in' brake fpipe pressure issufflcient to cause thetriple valve devices to suc-' cessively move tothe retarded release position throughout the train, the pistons 35 ofthe quick service valve devices on the successive cars being moved tothe quick serial release position, so as to vent fluid from the releasereservoir on each car to the brake pipe.

The release of the brakes throughout the train is thus accelerated, sothat the release is more nearly simultaneous, thus avoiding severeshocks and possible danger of a break-in-two due to the running out ofthe slack.

Upon a sudden reduction in brake pipe pressure to eflect an emergencyapplication of the brakes, the triple valve piston I4 is quickly shiftedtoward the left to emergency position, in which the spring-pressedgraduating stem 23 is forced back and the piston seals against thegasket 84.

With the piston H in emergency position, a passage 86 is uncovered bythe main slide valve l6, thereby permitting flow of fluid from theauxiliary reservoir 1 to the quick action piston cham ber 25. The quickaction piston 24 is then operated. to unseat the vent valve 26. Thepressure in chamber 21 being thereby instantly relieved, allows brakepipe fluid to raise the check valve 28 and flow rapidly through chambers21 and 3| to the brake cylinder, until brake cylinder and brake pipepressures nearly equalize, when the check valve 28 is returned to itsseat by the spring 29, preventing the pressure in the brake cylinderfrom flowing back into the brake pipe again. In this way a sudden localreduction in brake pipe pressure is produced which is transmittedserially throughout the train in the well known manner.

Also in emergency position of the triple valve device 8, a port 85 inthe main slide valve l6 registers with the brake cylinder passage 32,and fluid under pressure in the auxiliary reservoir I, as well as in theserial release reservoir I l, is thus permitted to equalize in the brakecylinder, as will be hereinafter more fully described.

When an emergency application of the brakes is initiated, the reductionin brake pipe pressure is also effective on the quick service valvedevice l0 and the high pressure valve device 15, and the quick servicevalve device I0 is actuated in the same manner as has been previouslydescribed in connection with a service application.

As soon as the pressure in piston chamber 16 of the high pressure valvedevice 15 has been suiliciently reduced below that in valve chamber 18on the other side of the piston 1.1, the higher pressure on the serialrelease reservoir side of said piston is able to overcome the resistanceof the spring and move the piston I1 and slide valve 19 to the left andthe piston seals against the gasket 81. In the movement of the piston 11toward the left, the spring stop 8i also moves toward the left untilfurther movement is prevented by the flange 88 on the spring stopengaging a shoulder 89 in the casing. In this position the end of. thestem of the piston 11 is spaced from the left hand end of the springstop 8|.

When the piston 11 and slide valve 19 move to ward the left, the slidevalve uncovers the passage 22, so that the valve chamber 18 is connectedwith the auxiliary reservoir 1. Fluid under pressure then flows from theserial release reservoir ll, through passages 50 and 5|, past the springstop II, to valve chamber 18, and thence through passages and 24 andpipe 20. to the auxiliary reservoir 1, thereby permitting'fl'uid underpressure in the serial release reservoir and the auxiliary reservoir toequalize in the brake cylinder and apply the brakes in emergency.

When it is desired, torelease the brakes after 5 an emergency, the brakepipe pressure is increased inthe usual way. When the brake pipe pressureeffective on the inner seated area of the piston 11 of the high pressurevalve device 15 has been increased a'predetermined amount, the spring ll19 moves the piston TI and slide valve I9 to the right, until the end ofthe piston stem engages the spring stop 8| which is, as has beenpreviously described, in a position to the left of that shown in thedrawing. Further movement of the piston 11 1 and slide valve 19 towardthe right, at this time, is thus prevented by the spring stop II, andthe piston is held in an intermediate position in which the valvechamber It on one side of the piston 11 is connected to the pistonchamber 18 on the other a side of said piston, through passage 90,around the piston.

Since the brake cylinder and auxiliary reservoir are connected .to thevalve chamber 18, through pipe 20, and passages 34 and 82, and since the25 serial release reservoir II is connected to the valve chamber 18,through passages 50 and ii, when the piston 11 is moved to theintermediate position, and the valve chamber II is connected, throughpassage 80, with piston chamber 18, fluid 39 from the auxiliaryreservoir, brake cylinder and serial release reservoir flows to thebrake pipe, thereby quickly recharging the brake pipe.

.As soon as the brake pipe pressure is thus further increased apredetermined amount, the 35 spring 80 moves the piston 11 and slidevalve 19 to the right until the piston seals against the seat rib 83,thereby cutting on the communication from the valve chamber 18 to thepiston chamber It. through the passage 90. In this movement of thepiston 11, the spring stop BI is also moved toward the right to theposition shown in the drawing.

It is thus evident that my invention provides for a higher emergencybrake cylinder pressure to be obtained when an emergency application ofthe brakes is made than has heretofore been obtained with the knowndevices, since the serial release reservoir l I is connected with theauxiliary reservoir through the operation of the 'ihigh pressure valvedevice 15. 50

Further, it will be observed that, after an emergency, when the brakepipe pressure is increased so as to effect the release of the brakes,should the triple valve piston ll fail for any reason to promptly moveto release position, the quick recharge of the brake pipe obtained byback dumping fluid from the brake cylinder, auxiliary reservoir andserial release reservoir into the brake pipe, as provided by myinvention, will be effective-in piston chamber I2, so that a higher difuf erential in fluid pressure will be promptly created on the oppositesides of piston I 4, and said piston will therefore be quickly moved torelease position.

While one illustrative embodiment of the invention has been described indetail, it is not my 35 intention to limit its scope to that embodimentor otherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire tosecure by Letters Pat- 1o ent, is:

1. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device operatedupon a sudden reduction in brake pipe pressure for vent- 1 tion of theadditional reservoir into the auxiliary reservoir.

2. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device operatedupon a sudden reduction in brake pipe pressure for venting fluid fromthe auxiliary reservoir to the brake cylinder to effect an emergencyapplication of the brakes, of an additional reservoir, a valve devicesubject to the opposing pressures of the brake pipe and said additionalreservoir and operable upon a predetermined reduction in brake pipepressure for venting fluid from the additional reservoir to theauxiliary reservoir until the additional reservoir has equalized intothe auxiliary reservoir, and a spring for opposing movement of saidvalve device to vent fluid from the additional reservoir.

- 3. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device operatedupon a sudden reduction in brake pipe pressure for venting fluid fromthe auxiliary reservoir to the brake cylinder to effect an emergencyapplication of the brakes, of an additional reservoir, and a valvedevice operable upon a predetermined reduction in brake pipe pressurefor controlling a communication through which fluid is vented from theadditional reservoir to the auxiliary reservoir and operable upon anincrease in brake pipe pressure for controlling a communication throughwhich fluid is vented from said auxiliary reservoir and said additionalreservoir to the brake pipe.

4. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device operatedupon a sudden reduction in brake pipe pressure for venting fluid fromthe auxiliary reservoir to the brake cylinder to eifect an emergencyapplication of the brakes, of an additional reservoir, and a valvedevice comprising a piston subject to the opposing pressures of thebrake pipe and said additional reservoir and operable upon apredetermined reduction in brake pipe pressure for controlling acommunication through which fluid is vented from the additionalreservoir to the auxiliary reservoir and operable upon an increase inbrake pipe pressure for controlling a communication through which fluidis vented from said auxiliary reservoir and said additional reservoir tothe brake pipe.

5. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device subjectto the opposing pressures of the brake pipe and auxiliary reservoir andoperated upon an increase in brake pipe pressure for releasing fluidfrom the brake cylinder, of an additional reservoir, and a valve devicesubject to the opposing pressures of the brake pipe and the additionalreservoir and operated upon an increase in brake pipe pressure forventing fluid from the auxiliary reservoir and the additional reservoirto the brake pipe.

6. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device operatedupon an increase in brake pipe pressure tor releasing fluid from thebrake cylinder, of an additional reservoir, and a valve device separatefrom the triple valve device and subject to the opposing pres- 5 suresof the additional reservoir and brake pipe and operated upon an increasein brake pipe pressure for venting fluid from the auxiliary reservoirand additional reservoir to the brake pipe to hasten the operation ofsaid triple valve device.

7. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device operatedupon an increase in brake pipe pressure for releasing fluid from thebrake cylinder, of an additional reservoir, a valve device subject tothe opposing pressures of the brake pipe and additional reservoir andoperated upon an increase in brake pipe pressure for venting fluid fromthe auxiliary reservoir and the additional reservoir to the brake pipe,and a spring for opposing movement of said valve device from theposition for venting fluid from said reservoirs to the brake pipe.

8. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device operatedupon an increase in brake pipe pressure for releasing fluid from thebrake cylinder, of an additional reservoir, a valve device subject tothe opposing pressures of the brake pipe and. additional reservoir andoperated upon an increase in brake pipe pressure for venting fluid fromthe auxiliary reservoir and additional reservoir to the brake pipe, anda spring for opposing movement of said valve device from the positionfor venting fluid from said reservoirs to the brake pipe and adapted topermit movement of the valve device only when the increase in brake pipepressure is sufficient to cause the operation of said triple valvedevice to release position.

9. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device operatedupon an increase in brake pipe pressure for releasing fluid from thebrake cylinder, of an additional reservoir adapted to be charged withfluid under pressure from the auxiliary reservoir, a check valve forpreventing back flow from the additional reservoir to the auxiliaryreservoir, a valve device subject to the opposing pressures of the brakepipe and additional reservoir and operated upon an increase in brakepipe pressure for venting fluid from the auxiliary reservoir andadditional reservoir to the brake pipe, and a spring for opposingmovement of said valve device from the position for venting fluid fromsaid reservoirs to the brake pipe and adapted to permit movement of thevalve device only when the increase in brake pipe pressure is suflicientto cause the operation of said triple valve device to release position.

10. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device operatedupon a sudden reduction in brake pipe pressure for venting fluid fromthe auxiliary reservoir to the brake cylinder to effect an emergencyapplication of the brakes, of an additional reservoir adapted to becharged with fluid under pressure from the auxiliary reservoir, a checkvalve for preventing back flow from the additional reservoir to theauxiliary reservoir, and a valve device operative at a predetermineddifferential in pressures between the brake pipe and additionalreservoir 75.

for supplying fluid under pressure from the additional reservoir to theauxiliary reservoir with the triple valve device in emergencyapplication position.

11. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device operatedupon an increase in brake pipe pressure for releasing fluid from thebrake cylinder, of an additional reservoir adapted to be charged withfluid under pressure from the auxiliary reservoir, a check valve forpreventing back flow from the additional reservoir to the auxiliaryreservoir, means for venting fluid from the auxiliary reservoir andadditional reservoir to the brake pipe, comprising a piston subject onone side to the pressure of a chamber connected to said additionalreservoir and on the opposite side to the pressure'of a chamberconnected to the brake pipe, said piston being adapted to controlcommunication through a passage connecting said chambers, and meanscarried by the piston for controlling communication from said firstnamed chamber to the auxiliary reservoir, and a spring for opposingmovement of said piston from the position for establishing communicationbetween said chambers and adapted to permit movement of said piston onlywhen the increase in brake pipe pressure is suflicient to cause theoperation of said triple valve device to release position.

12. In a fluid pressure brake, the combination with a brake pipe,auxiliary reservoir, brake cylinder, and a triple valve device operatedupon an increase in brake pipe pressure for releasing fluid from thebrake cylinder, of means for quickly recharging the brake pipe to eilectthe operation of said triple valve device, comprising an additionalreservoir, a piston subject on one side to the pressure of a chamberconnected to said additional reservoir and on the opposite side to the 5pressure of a chamber connected to the brake pipe, said pistoncontrolling a communication through which both of said chambers areconnected, means carried by the piston for controlling communicationfrom said first named cham- 1o her to the auxiliary reservoir, and aspring for opposing movement of said piston from the position forestablishing communication between said chambers and adapted to permitmovement of said piston to a position in which the com- 15 municationbetween said chambers is cut of! only when the increase in brake pipepressure is sumcient to cause the operation of said triple valve deviceto release position.

13. In a fluid pressure brake, the combination so with a brake pipe, anauxiliary reservoir, an additional reservoir and a quick service valvedevice operated upon a reduction in brake pipe pressure for effecting alocal reduction in brake pipe pressure, of a filling piece interposedbe- 2L tween said additional reservoir and said valve device, and anemergency valve device carried by said filling piece and operated upon apredetermined reduction in brake pipe pressure for connecting saidadditional reservoir to the auxiliary i. reservoir, said filling piecehaving passages connecting said emergency valve device to the brake pipeand to the auxiliary reservoir.

JOSEPH c. ircctms. as

